Here below we post a list of
Articles already accepted for publication in Issue 4/(December) 2022 of Hidraulica Magazine.
The list displays the article title, author(s) and affiliation, and also the article abstract.
Full-length article will be available online only after publication.
- Modification of Cavitation Erosion Resistance of Aluminum Alloy 7075 by Maintaining of Artificial Aging Heat Treatment at 180°C
Prof.PhD.Eng. Ilare BORDEAȘU1, Dipl. Eng. Alexandru Nicolae LUCA1, PhD.Eng. Iosif LAZĂR1, Dipl. Eng. Dragoș LAZĂR1, Lecturer PhD.Eng. Rodica BĂDĂRĂU1, Prof.PhD.Eng. Brandușa GHIBAN1, Dipl. Eng. Andreea Daniela BUZATU1, Dipl. Eng. Alin Mihai DEMIAN1, Dipl. Eng. Ovidiu Petrișor ODAGIU1, Assoc.Prof.PhD.Eng. Lavinia Mădălina MICU2
1Politehnica University of Timisoara, Romania
2Banat University of Agricultural Sciences and Veterinary Medicine of Timisoara, Romania
The use of volume heat treatments aims to change the microstructure and the values of the mechanical properties, with homogeneous distribution in the volume of the part, so as to confer resistance to various stresses. From the point of view of the hydrodynamic stresses of the microjets generated by the cavitation mechanism, these treatments ensure an increase in the life of the required surface. In the case of aluminum-based alloys, volume thermal treatments do not produce important changes in the structural phase, but they cause important changes in the values of the mechanical properties. As these alloys have small specific masses and good mechanical properties, research is currently being resumed aimed at extending their use to parts that work in cavitation such as: propellers of motor boats and pleasure boats, pump rotors in the cooling system of thermal engines and aircraft wings. In this sense, the vibratory cavitation tests are carried out on aluminum alloy 7075 subjected to volumetric thermal treatment of artificial aging at 1800C with a holding time of 24 hours. The comparison with the results previously obtained on the delivered state and the regime with the same temperature and duration of one hour shows that the effect of increasing the duration of the heat treatment leads to a significant increase compared to the state of delivery and slightly different from that obtained by the one with a duration of one hour.
-
Mathematical Modeling, Laboratory Testing and Numerical Simulation of a Servo-Pump as Part of a Closed Circuit Primary Control Hydrostatic Transmission for Multi-Purpose Trucks
PhD. Stud. Eng. Alexandru-Polifron CHIRIȚĂ1,2, Prof. PhD. Eng. Cristian PAVEL1
1Technical University of Civil Engineering of Bucharest (UTCB), Faculty of Technological Equipment, Bucharest, Romania
2National Institute of Research & Development for Optoelectronics / INOE 2000 – Subsidiary Hydraulics and Pneumatics Research Institute / IHP, Bucharest, Romania
The current paper presents the dynamic mathematical models of the components of a hydrostatic transmission, the results of physical tests performed in the laboratory on a servo-pump that is part of a closed circuit primary control hydrostatic transmission, and its numerical simulation results. The acquisition of the experimental data as well as the control of the experimental stand have been carried out with the LabVIEW application, while the numerical simulation has been carried out by using the AMESim software; in order for the results of the numerical simulation to be as close as possible to those obtained in the laboratory, the library of hydraulic components that take into account the influence of temperature on the hydraulic fluid and on the hydraulic components of the transmission has been used.
-
Effective Solutions to Reduce Energy Consumption in the Turbo-Blowers of a Sewage Treatment Plant
Prof.PhD.Eng. Mariana PANAITESCU1, Prof.PhD.Eng. Fănel-Viorel PANAITESCU1, Lect. PhD. Eng. Alexandru-Andrei SCUPI1
1Constanta Maritime University, Romania
Since the energy consumption of the turbo blowers represents 68% of the energy consumption of the station, it was sought to reduce this consumption by installing oxygen sensors in the bioreactors; these sensors detect the reaching of the optimal (maximum) oxygen threshold of 2.0% and at this moment they partially close the butterfly valves from the discharge of the turbo blowers, which leads to the reduction of the flow rate and implicitly the energy consumption of the turbo blowers. Through the SEAU’s SCADA system for the oxygen volume, the necessary data were obtained to calculate the percentage opening of the butterfly valves from the discharge of the turbo blowers in order to monitor the efficiency of the regulation system, and implicitly, the reduction of energy consumption. The following were calculated: the initial annual consumption established by design, the three-day consumption, the value of the optimized energy, the value of the energy saved, obtaining the economic efficiency of the proposed solution. The regulation system tests the oxygen concentration in the aerobic bioreactor and maintains its value at around 1.5%. The rapid control valve system is set to operate in the 15%-65% opening range. When the oxygen detector detects reaching the 1.5% threshold, the valves open and the air flow increases; at the same time, the power consumed by the turbo blower obviously increases. The diagram of the variation of the oxygen regime and the response of the opening of the turbocharger discharge valve are represented in parallel.
-
Aspects regarding the Use of Hydraulic Motors
Prof. PhD. math. Alexandru BOBE1, PhD. Eng. Tiberiu AXINTE2, PhD. Eng. Cătălin NUȚU3, Dipl. Eng. Cătălin FRĂȚILĂ2, Dipl. Eng. Mihai DIACONU2
1Ovidius University of Constanta, Romania
2Research and Innovation Center for Navy, Romania
3Constanta Maritime University, Romania
This article represents research regarding use of hydraulic motors. The role of hydraulic motors is to convert fluid pressure into rotary motion. The motor considered in this article is a hydraulic actuator. The hydraulic motor works only with a pump unit. A pump unit usually has a maxim pressure of 6·105 Pa. Hydraulic motors can be used for various applications, such as: excavators, shredders, drilling rigs, winches, crane drives, cooling fan drivers, feeder, roll mills, launch and recovery systems (LARS), etc. After introduction, the authors study two pneumatic circuits using hydraulic motors. The first one has only one device (hydraulic motor 1-1). The second one has two such devices (hydraulic motors 2-1 and 2-2). Afterwards, the two corresponding electro-hydraulic schemes are presented: a simple electro-hydraulic scheme that has only one hydraulic motor and the second electro-hydraulic scheme, which has a hydraulic motor and logic module. The hydraulic and electro-hydraulic schemes given in this paper are designed using FluidSim software from Festo.
